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<FONT color="green">001</FONT>    package gates;<a name="line.1"></a>
<FONT color="green">002</FONT>    <a name="line.2"></a>
<FONT color="green">003</FONT>    import register.Register;<a name="line.3"></a>
<FONT color="green">004</FONT>    import gates.FunctionGate;<a name="line.4"></a>
<FONT color="green">005</FONT>    <a name="line.5"></a>
<FONT color="green">006</FONT>    /**<a name="line.6"></a>
<FONT color="green">007</FONT>     * This is the Marking subroutine M of the grover iteration. Also referred to as oracle. <a name="line.7"></a>
<FONT color="green">008</FONT>     * if x=t is searched state, and x != t any other state let:<a name="line.8"></a>
<FONT color="green">009</FONT>     * f(x !=t)=0 and f(x=t) = 1<a name="line.9"></a>
<FONT color="green">010</FONT>     * M: |x&gt; --&gt; (-1)^f(x)|x&gt; <a name="line.10"></a>
<FONT color="green">011</FONT>     * <a name="line.11"></a>
<FONT color="green">012</FONT>     * @author Jan Zaucha<a name="line.12"></a>
<FONT color="green">013</FONT>     *<a name="line.13"></a>
<FONT color="green">014</FONT>     */<a name="line.14"></a>
<FONT color="green">015</FONT>    public class OracleFunction extends FunctionGate {<a name="line.15"></a>
<FONT color="green">016</FONT>    <a name="line.16"></a>
<FONT color="green">017</FONT>            /** Searched element the algorithm is looking to find */<a name="line.17"></a>
<FONT color="green">018</FONT>            private int searched;<a name="line.18"></a>
<FONT color="green">019</FONT>    <a name="line.19"></a>
<FONT color="green">020</FONT>            /**<a name="line.20"></a>
<FONT color="green">021</FONT>             * Constructor <a name="line.21"></a>
<FONT color="green">022</FONT>             * @param searched the searched element<a name="line.22"></a>
<FONT color="green">023</FONT>             */<a name="line.23"></a>
<FONT color="green">024</FONT>            protected OracleFunction(int searched){<a name="line.24"></a>
<FONT color="green">025</FONT>                    this.searched = searched;<a name="line.25"></a>
<FONT color="green">026</FONT>            }<a name="line.26"></a>
<FONT color="green">027</FONT>    <a name="line.27"></a>
<FONT color="green">028</FONT>    <a name="line.28"></a>
<FONT color="green">029</FONT>            /**<a name="line.29"></a>
<FONT color="green">030</FONT>             * Returns the name of the gate regardless of representation.<a name="line.30"></a>
<FONT color="green">031</FONT>             */<a name="line.31"></a>
<FONT color="green">032</FONT>            public String getName() {<a name="line.32"></a>
<FONT color="green">033</FONT>                    return "Oracle";<a name="line.33"></a>
<FONT color="green">034</FONT>            }<a name="line.34"></a>
<FONT color="green">035</FONT>    <a name="line.35"></a>
<FONT color="green">036</FONT>            /**<a name="line.36"></a>
<FONT color="green">037</FONT>             * Flips just the searched state<a name="line.37"></a>
<FONT color="green">038</FONT>             *<a name="line.38"></a>
<FONT color="green">039</FONT>             * @param r the register <a name="line.39"></a>
<FONT color="green">040</FONT>             */<a name="line.40"></a>
<FONT color="green">041</FONT>            public void apply(Register r) {<a name="line.41"></a>
<FONT color="green">042</FONT>                    if (searched &lt; 0 || searched &gt;= r.getNumStates()){<a name="line.42"></a>
<FONT color="green">043</FONT>                            throw new IllegalArgumentException("Searched state is not in the register. " +<a name="line.43"></a>
<FONT color="green">044</FONT>                                            "Searched state: |" +searched + "&gt;  Number of states in register: " + r.getNumStates() );<a name="line.44"></a>
<FONT color="green">045</FONT>                    }<a name="line.45"></a>
<FONT color="green">046</FONT>                    r.getElement(0, searched).negate();<a name="line.46"></a>
<FONT color="green">047</FONT>    <a name="line.47"></a>
<FONT color="green">048</FONT>            }<a name="line.48"></a>
<FONT color="green">049</FONT>    <a name="line.49"></a>
<FONT color="green">050</FONT>    <a name="line.50"></a>
<FONT color="green">051</FONT>    <a name="line.51"></a>
<FONT color="green">052</FONT>    }<a name="line.52"></a>




























































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